“It’s important to make a distinction between the terms ‘murder’ and ‘assassinate,’” asserts Cillian Murphy’s Jozef Gabcik midway through director Sean Ellis’s World War II drama-thriller “Anthropoid.” Murder, he says, implies that you are snuffing out a life worth living. There is no room for moral ambiguity in his mission. Gabcik is a soldier for the underground Czech resistance. He’s tasked with killing the top-ranking Nazi official with the iron heart, Adolf Hitler’s third-in-command, Reinhard Heydrich: Reichsprotektor of Bohemia and Moravia, “The Butcher of Prague” and one of the main architects of the Holocaust. In fact, he was the highest ranking Nazi official to be assassinated during the war.

“Anthropoid” was named after the covert operation sanctioned and carried out by the Czech government in exile between 1941 and 1942. Unlike more “high-minded” war thrillers like “Munich” or “The Thin Red Line,” this film is not a rumination on the swinging pendulum of ethics that occurs on both sides during times of war. Rather, it is a look at the bleak reality of conflict, its effect on the delicate human psyche and the seeming futility of trying to fight against the many-headed beast that is evil. “War is not romantic,” says another character and while its overtly Hollywood-ized method of storytelling and aesthetic says otherwise, the movie hits on some really crucial points in some not-so-easy ways.

We open on that cliched mainstay of the modern action-thriller — expositional text over grainy stock footage that fills us in on events that led to the war including The Munich Agreement, Chamberlain’s failed policy of appeasement, Germany’s annexation of Czechoslovakia, a precursor to Hitler’s conquest of Europe. Then Gabcik (Murphy) and Jan Kubis (Jamie Dornan) parachute into Nazi-occupied Czechoslovakia in the dead of a frosty winter night to begin carrying out their mission. And while the real-life Gabcik and Kubis were not as handsomely debonair as the leading Hollywood actors who play them, Murphy and Dornan do a real convincing job at bringing these brave men to life, even if they can’t always hide their native Irish brogues.

As the two cavort around Prague — there are some really beautiful historical sites that the film crew was actually able to use for the movie — they make contact with members of the Czech resistance and plan the assassination. “Anthropoid” can seem a little slow, especially when it tries to introduce thin romantic foils for the two operatives played by Anna Geislerova and Charlotte Le Bon. But don’t let the sluggish pace fool you; it’s a slow burn, filling the characters with dread and self-doubt. While Heydrich barely gets any screen time, his presence and the very evil of the Third Reich hang over the characters like a palpable, morale-sapping cloud of toxins. For instance, having to shoot one’s self or swallow a cyanide capsule just so they can’t be taken alive by the Gestapo do very little in the way of motivation. This comes across in the cinematography, which utilizes claustrophobic, shaky close-ups and diffused shafts of light. Moreover, some resistance members muse on the very practicality of the mission. Do the cons vastly outweigh the pros? Will Germany seek horrible retribution for Heydrich’s death? In reality, this turned out to be true when Hitler ended up murdering and razing entire villages as revenge.

Once the deed is done (again, not much screen time), the film kicks into high gear as the Nazis crack down on Prague in an attempt to find the culprits. Some scenes involving torture and weak human nature are downright hard to watch, something you might not have expected from most of the lackluster beginning. While unpleasant to see, a Gestapo interrogator breaking a young man’s fingers with a hammer or a woman wetting herself under duress are necessary imagery to convey the true horrors of that time and place in world history.

The movie ends with a spectacular battle in a church between the resistance fighters and overwhelming German forces. The final epic showdown against impossible odds has become somewhat of a cliche in war movies of late, starting with “Saving Private Ryan” and seen most recently in “Fury.” However, this fight actually happened and it’s breathtaking to see on screen even if there’s some lousy reincorporation and an on-the-nose allusion to Shakespeare’s “Julius Caesar.” Even though history, and the movie’s end card, tells us these men were eventually killed after holding the church for six hours, Ellis’s heart-pumping direction still makes us hold out hope that they will be successful, or at the very least, kill just one more Nazi.

As we move farther away from the horrors of World War II, it is important to tell these stories not only of evil, but of the selfless attempts to stop it. As the old platitude goes, evil flourishes when good men do nothing. Like other well-crafted WWII-era assassination flicks like “Valkyrie,” “Anthropoid” tells the story of brave men who dared to fight against an enormous monster in a time when many were content to sit on their hands and turn a blind eye to murder, torture, humiliation and thievery. It can teach us a lesson that some action is always better than inaction, that by standing up for what is right, we can truly say “Never Again.”